Questions and discussion for this lecture live here. Fire away by hitting Reply below 
Sean,
You are an excellent teacher. These two lectures in “what is non-linearity” really sums up this topic quite nicely in order to dive in. In my Steel Design class, I’m currently in at Uni, our professor has asked us to write about how we should go about teaching, how we tackle second order analysis of structures. My take on it thus far, after almost completing your direct stiffness method course, is that we need to teach the idea of stiffness at the same time we start learning Young’s Modulus. The ideas are so linked however we don’t really learn about F=kd unless we take a finite element analysis class. And the crazy thing is, from what I can tell, most software analysis uses FEA. So to think you can easy make it through a bachelor’s without taking a FEA course, because it isn’t a requirement, and therefore never really start to understand this relationship between Force and displacement. Like all things, there are multiple ways to solve complicated problems, however you really start to see the leverage of matrix analysis and how software makes that possible.
Anyways, Thanks for the content. Your courses are seriously invaluable. Keep up the good work!
Best,
Anthony
Thanks Anthony - I really appreciate the comment and I’m really pleased to hear that you’re finding my courses helpful.
As with so many things in engineering, almost every topic is linked, at a fundamental level at least. The trick is trying to spot the underlying connections. For example, early on, you probably came across Hooke’s law - this is fundamentally the concept we are super-charging with our matrix analysis.
My advice is always to try and relate everything back to the fundamentals - it can be very easy to get lost on the details sometimes!!
Cheers,
Seán